1. Field of the Invention
The present invention relates to valves for use in conjunction with the filling and dispensing of beer and related liquids from keg-like containers. More particularly, this invention pertains to apparatus for enhancing the safe disposal of "throwaway" containers for carbonated beverages.
2. Description of the Prior Art
In the past, large volumes of beer for consumption have been stored, shipped in and dispensed from metal kegs of closed or single entry design. In such a keg, a so-called Sanke system is nearly-universally employed for regulating the flow of beer into and from the keg. A Sanke system comprises a spear tube and a valve of the type that includes inner and outer valved chambers to accommodate flows of pressurizing gas and of liquid responsive to the force exerted by such pressurizing gas.
Automatic washing and racking apparatus cleans, sterilizes and refills the combination of keg and valve. The reprocessing of such containers can be relatively expensive. However, the relatively substantial investment represented by such a system makes it mandatory to invest in such repeated processing.
Sanke-type valves commonly include apertures that permit the pressurized flow of beverage to impact the bottom of the (inverted) keg with great force during the filling or racking process. As a result, the beverage is substantially agitated and, in the case of beer, a substantial amount of foam or "head" is generated. As will be explained below, this head is quite undesirable in terms of both beverage waste and flavor.
Efforts to reduce cost have led to the development plastic kegs for throw-away use. Such kegs are sold as a unit that includes a valve and beverage for picnic and related uses. The plastic keg is routinely of spherical design and includes a top, crimped to the mouth of the keg, that has a pair of flapper valves therein. One of such valves regulates a flow of pressurizing gas and the other regulates beverage flow. Unlike the metal kegs that include Sanke-type valves, plastic keg systems are filled with beverage prior to crimping the flapper valve top. As a result, anerobic bacteria often contaminate the beverage which results, in the case of beer, in an unsatisfactorily short shelf life.
Dewes, Gunn and Hagan have disclosed a new valve system in pending U.S. patent application Ser. No. 887,741, referenced above, that is adapted to enhance and facilitate, and therefore render more feasible, the use of throwaway containers for beverages, including those, such as soft drinks and beer, that contain carbonation. While the advantages of such throwaway containers are apparent, their use can lead to problems that are not encountered in the use of reusable containers.
An unavoidable residual amount of beverage exists in a keg or other container after it is effectively "empty". This can result from a number of factors including the distance between the bottom of the spear and the bottom of the container, insufficient pressurization of the beverage and container geometry. While no particular problem is posed by such residual beverage in a reusable metal keg, its presence in a plastic container or keg that is intended, by virtue of its economical price, to be thrown away, can be dangerous.
In plastic containers or kegs of the type that utilize a ball-type valve of the sort discussed in the referenced patent application, the valve is sealed to the container. Thus, an entire unit, including keg and valve will be discarded by the user. As is discussed below, the arrangement of such a valve is urged by spring means into a sealing relationship with the exception of the times in which a filling head or a tap is inserted into, and thereby depresses, the ball valve. Clearly the interior of the keg will be sealed after the tap is removed and the keg is discarded. Often, the user can be expected to discard the keg into an incinerator or to expose the used keg to strong sunlight. In either event, the sealed container, including a residue of carbonated liquid, poses a hazard. Much like an aerosol can, such a keg is subject to explosion.